Critical thermal maxima and upper lethal temperatures for the calanoid copepods Acartia tonsa and A. clausi

1974 ◽  
Vol 27 (3) ◽  
pp. 219-223 ◽  
Author(s):  
J. G. Gonz�lez
Keyword(s):  
Acartia Tonsa ◽  
Calanoid Copepods ◽  
Lethal Temperatures ◽  
Critical Thermal Maxima

A Study of Grazing Behavior of Copepods Using Digital Holographic Cinematography

2008 ◽  
Author(s):  
Siddharth Talapatra ◽  
Jiarong Hong ◽  
Jian Sheng ◽  
Becky Waggett ◽  
Pat Tester ◽  
...  
Keyword(s):  
Flow Field ◽  
Spatial Resolution ◽  
High Speed ◽  
Acartia Tonsa ◽  
Copepod Species ◽  
Calanoid Copepods ◽  
Grazing Behavior ◽  
Karlodinium Veneficum ◽  
Different Strains ◽  
Neutrally Buoyant

Generating proper feeding currents for entraining prey is one of the important features in the grazing behavior of (∼1mm) copepods. These feeding currents vary with the copepod species, as well as with the species or strains and concentration of prey (∼10 μm) dinoflagellates. Calanoid copepods also hover for a while, while slowly sinking, and then intermittently jump to a different location. In our study, we employed high speed digital holographic cinematography to measure elements of the flow field around copepods in an environment seeded with dinoflagellates. In most cases, the flow field and feeding currents were characterized based on the trajectories of the dinoflagellates. However, in some of the tests we also added neutrally buoyant 20 μm particles as independent flow tracers. At low magnifications, we simultaneously recorded two perpendicular views to obtain the same spatial resolution in all directions. Data were recorded at varying magnifications and frame rates. In recent experiments, we exposed the copepods to different strains of the same dinoflagellate species that have varying levels of toxicity, and measured the resulting changes to the grazing behavior of the copepods. Here we present results from two of these experimental setups: Acartia tonsa with Karlodinium veneficum (non toxic strain) and Acartia tonsa in particle seeded flow. Issues such as swimming characteristics, feeding classification (raptorial vs. filter feeding approaches) and copepod response to different environmental settings were addressed.

scholarly journals Comparison of upper sublethal and lethal temperatures in three species of rice planthoppers

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Shahbaz Ali ◽  
Pei Li ◽  
Asad Ali ◽  
Maolin Hou
Keyword(s):  
Plant Material ◽  
Brown Planthopper ◽  
Nilaparvata Lugens ◽  
Laodelphax Striatellus ◽  
Sogatella Furcifera ◽  
Lethal Temperatures ◽  
Rice Planthoppers ◽  
Critical Thermal Maxima ◽  
Increasing Temperature ◽  
Occurrence Patterns

Abstract Temperature is an important environmental factor for ectotherms’ fitness and survival. The upper sublethal and lethal temperatures were compared between adults of three closely related destructive planthopper species, the small brown planthopper (Laodelphax striatellus, SBPH), the brown planthopper (Nilaparvata lugens, BPH), and the white-backed planthopper (Sogatella furcifera, WBPH) in the absence and presence of the host plant (Oryza sativa, var. Taichong1). Values of the critical thermal maxima (CTmax) were higher in SBPH than in both BPH and WBPH and higher in BPH than in WBPH, and values of the heat coma temperatures (HCT) were higher in both BPH and SBPH than in WBPH. CTmax and HCT values were higher in the presence than in the absence of plant material. Between sexes, females generally showed higher CTmax and HCT than males. The upper lethal temperatures (ULT50) measured in the absence of plant material were not significantly different among the planthopper species. The planthoppers also exhibited different behaviors in an increasing temperature regime, with fewer insects dropping-off from the plant in SBPH than in BPH and WBPH. These results indicate that SBPH and BPH are more heat tolerant than WBPH. The findings highlight the biological divergence in closely related planthopper species and the importance of performing the heat tolerance measurement in an ecologically relevant setting, which serves to predict seasonal and spatial occurrence patterns of the destructive planthopper species.

Culture of Calanoid Copepods in Synthetic Sea Water

1969 ◽  
Vol 26 (1) ◽  
pp. 150-153 ◽  
Author(s):  
Donald R. Heinle
Keyword(s):  
Sea Water ◽  
Acartia Tonsa ◽  
Calanoid Copepods ◽  
Sea Salts ◽  
Eurytemora Affinis

The calanoid copepods Acartia tonsa and Eurytemora affinis were successfully cultured in two commercial synthetic sea salts. Success of a medium was measured by its ability to sustain a population of copepods that was subjected to moderate rates of harvest.

On the morphology and life-history of Hemiurus luehei Odhner, 1905 (Digenea: Hemiuridae)

1990 ◽  
Vol 64 (3) ◽  
pp. 193-202 ◽  
Author(s):  
Marianne Køie
Keyword(s):  
Atlantic Coast ◽  
Acartia Tonsa ◽  
Salmonid Fishes ◽  
Calanoid Copepods ◽  
Delivery Tube ◽  
Intermediate Hosts ◽  
Free Swimming ◽  
Temora Longicornis ◽  
History Of ◽  
The Baltic

ABSTRACTPreviously undescribed cystophorous cercariae which develop in sporocyst germinal sacs in the tectibranch opisthobranch Philine denticulata (Adams) are shown to be cercariae of Hemiurus luehei Odhner, 1905 (Hemiuridae), a common stomach parasite of clupeid and salmonid fishes off the Atlantic coast of Europe, in the Baltic and the Mediterranean Sea. The free-swimming cercariae are seized by calanoid copepods. Temora longicornis (Müller) and Acartia tonsa Dana acted as suitable experimental intermediate hosts. Pressure by the copepod mouth appendages causes delivery tube eversion and the injection of the cercarcial body into the haemocoel. Sagitta sp. was found naturally infected with a metacercaria of H. luehei. The cystophorous cercaria and metacercaria are described using light and scanning electron microscopy. Adults from herring were examined under the stereoscan electron microscope.

Toxicological Comparison of Natural and Cultured Populations of Acartia tonsa to Cadmium, Copper, and Mercury

1978 ◽  
Vol 35 (10) ◽  
pp. 1366-1369 ◽  
Author(s):  
S. L. Sosnowski ◽  
J. H. Gentile
Keyword(s):  
Key Words ◽  
Response Variability ◽  
Nutritional Condition ◽  
Acartia Tonsa ◽  
Response Patterns ◽  
Calanoid Copepods ◽  
Different Response

Cultured Acartia tonsa manifested a reproducible toxicological response through six generations. There were no statistically significant differences in the responses of F1 and F6 generations to cadmium, copper, and mercury. Cultured and field populations (parental) exposed to cadmium did not manifest statistically different response patterns. The response variability of cultured populations was less than that of field populations. The 96-h LC50 concentrations for cultured (F1) populations were 90 μg Cd/L, 31 μgCu/L, and 10 μg Hg/L. The presence and abundance of ova and unicellular glands in the circumesophogeal region were used as criteria for evaluating the nutritional condition of test populations. Key words: marine, metals, bioassay, culture, calanoid copepods, toxicity, histology, filial generations

Ultrastructural identification of three types of sensory setae on copepod antennae

1995 ◽  
Vol 53 ◽  
pp. 956-957
Author(s):  
T. M. Weatherby ◽  
P.H. Lenz
Keyword(s):  
Phase Locking ◽  
Membrane Surface ◽  
Reaction Times ◽  
High Sensitivity ◽  
Structural Features ◽  
Calanoid Copepods ◽  
Marine Food Webs ◽  
Dendritic Membrane ◽  
Ultrastructural Characterization

Crustaceans, as well as other arthropods, are covered with sensory setae and hairs, including mechanoand chemosensory sensillae with a ciliary origin. Calanoid copepods are small planktonic crustaceans forming a major link in marine food webs. In conjunction with behavioral and physiological studies of the antennae of calanoids, we undertook the ultrastructural characterization of sensory setae on the antennae of Pleuromamma xiphias.Distal mechanoreceptive setae exhibit exceptional behavioral and physiological performance characteristics: high sensitivity (<10 nm displacements), fast reaction times (<1 msec latency) and phase locking to high frequencies (1-2 kHz). Unusual structural features of the mechanoreceptors are likely to be related to their physiological sensitivity. These features include a large number (up to 3000) of microtubules in each sensory cell dendrite, arising from or anchored to electron dense rods associated with the ciliary basal body microtubule doublets. The microtubules are arranged in a regular array, with bridges between and within rows. These bundles of microtubules extend far into each mechanoreceptive seta and terminate in a staggered fashion along the dendritic membrane, contacting a large membrane surface area and providing a large potential site of mechanotransduction.

Seasonal diving and foraging behaviour of Eastern Canada-West Greenland bowhead whales

2020 ◽  
Vol 643 ◽  
pp. 197-217 ◽  
Author(s):  
SME Fortune ◽  
SH Ferguson ◽  
AW Trites ◽  
B LeBlanc ◽  
V LeMay ◽  
...  
Keyword(s):  
Climate Change ◽  
Late Summer ◽  
Calanoid Copepods ◽  
Eastern Canada ◽  
West Greenland ◽  
Bowhead Whales ◽  
Seasonal Movement ◽  
Dive Behaviour ◽  
Calanus Glacialis ◽  
Canada West

Climate change may affect the foraging success of bowhead whales Balaena mysticetus by altering the diversity and abundance of zooplankton species available as food. However, assessing climate-induced impacts first requires documenting feeding conditions under current environmental conditions. We collected seasonal movement and dive-behaviour data from 25 Eastern Canada-West Greenland bowheads instrumented with time-depth telemetry tags and used state-space models to examine whale movements and dive behaviours. Zooplankton samples were also collected in Cumberland Sound (CS) to determine species composition and biomass. We found that CS was used seasonally by 14 of the 25 tagged whales. Area-restricted movement was the dominant behaviour in CS, suggesting that the tagged whales allocated considerable time to feeding. Prey sampling data suggested that bowheads were exploiting energy-rich Arctic copepods such as Calanus glacialis and C. hyperboreus during summer. Dive behaviour changed seasonally in CS. Most notably, probable feeding dives were substantially shallower during spring and summer compared to fall and winter. These seasonal changes in dive depths likely reflect changes in the vertical distribution of calanoid copepods, which are known to suspend development and overwinter at depth during fall and winter when availability of their phytoplankton prey is presumed to be lower. Overall, CS appears to be an important year-round foraging habitat for bowheads, but is particularly important during the late summer and fall. Whether CS will remain a reliable feeding area for bowhead whales under climate change is not yet known.

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